Here's one for the right seasoned mechanic:
Does the lift pump regulate its flow according to pressure, or does it flow constant (relative to rpm) ?
The question is for those of us contemplating a looped return for veggy oil use, where extra fuel from the IP and injectors would have nowhere to go but back to the IP.
In the stock setup, the extra fuel is returned to the tank, and a lot is extra, as I understand.
So, if there is a looped return, with the use of much less fuel, is the lift pump regulating its flow or just trying to pump a set amount of fuel?

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Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

Or, can anyone direct me to a source of information about pressure stats for lift pumps?

__________________
Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

I was always under the impression that the lift pumps were constant pressure , not constant flow.
Here is tha answer
here is the specification for the 300D OM617 engine fuel pump (lift pump)
BTW, 1 Bar is around 14 psi, so 0.8Bar is ~11 psi.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

I am having a little trouble trying to wrap my brain around those specs. I don't see a max anywhere, but a min. .8 bar; and what does delivery end pressure at min 1.3 bar at 3000 rpm imply?
Would that be like 18 or 19 psi?
I guess next I have to figure out what the IP will take...
Probably at least what the lift pump can dish out.

And if the flow is regulated according to pressure, doesn't this mean I should just shut up and get on with the plumbing?

Thanks for humouring me in my pressure worries..

__________________
Think Alternative Energy!
300CD '80 (now gone but not forgotten...)